Effective in release Spring 2017, Salesforce Connector provides two modes of Salesforce login. When you create a Salesforce connection, you can either select Standard or OAuth type. The Standard connection accepts username and password. The OAuth connection accepts the service endpoint URL and OAuth access token.

Informatica Cloud OAuth Utility:

Informatica Cloud OAuth utility is a standalone tool that you can use to generate access tokens for Salesforce OAuth connection. Perform the following steps to generate access token: 

• Contact Informatica Global Customer Support to obtain the OAuth utility package, oauth-tool.zip.
• Extract oauth-tool.zip.
• Navigate to oauth-tool\tomcat\conf.
• Open the server.xml file to update the mystore.jks file path.
• Update the mystore.jks file path to the one on your system where you unzipped the oauth-tool.zip file.
• Navigate to oauth-tool\tomcat\bin.
• Double-click catalina.bat to run the batch file or same could be run thru command with Catalina.bat start.
• Open the browser window and paste the following URL in the address bar:
  For production instance:  http://localhost:8090/salesforce/initiateoauth
  For sandbox instance: http://localhost:8090/salesforce/test/initiateoauth
  
• The Salesforce Log In page appears.
• Log in to Salesforce using your credentials. You can view the OAuth access token generated with the other details, such as signature and instance URL. For example:

• {"access_token":"00Di0000000eDzY!AQQAQDsfpPY78S7GQ1btSmy6vWv3Losf1oUfSI24URVoXbG_Bllsk4ybtF2xyX5H29rrc8pCpC1kANpZq6b0PI_m.Ldy0q7T","signature":"uThh23rE58+p8Glae3gZ0u0XZR0QSCrOumppvld6V1k=","scope":"api","instance_url":"https://na15.salesforce.com","id":"https://login.salesforce.com/id/00Di0000000eDzYEAU/005i0000001GWBKAA4","token_type":"Bearer","issued_at":"1444727905179"} Access token - 00Di0000000eDzY!AQQAQDsfpPY78S7GQ1btSmy6vWv3Losf1oUfSI24URVoXbG_Bllsk4ybtF2xyX5H29rrc8pCpC1kANpZq6b0PI_m.Ldy0q7T